Aqueous fluorocarbon telomer dispersion and process of preparing same



United States Patent 3,105,824 AQUEOUS FLUORGCARBON TELOMER DISPER- SIONAND PROCESS OF PREPARING SAME Larry Quentin Green, Wilmington, Del, andRalph Waiter Moses, Deepwater, N.J., assignors to E. I. du Pont deNemours and Company, Wilmington, Del, a corporation of Delaware NoDrawing. Filed May 3, 1960, Ser. No. 26,428 3 vClaims. (Cl. 260-296)This invention is directed to a novel aqueous fluoro carbon telomerdispersion, and more particularly, to a stable dispersion in water of afluorocarbon telomer having wax-like characteristics obtained byreacting tetrafiuoroethylene in the presence of methylcyclohexane andl,1,2-trichlorotrifluoroeth-ane. The resultant tetrafluoroethylenetelomer dispersion is useful as a lubricant in the cold forming ofmetals such as wire drawing, stamping and cutting as a lubricant inprinting inks, as a release agent for paper, as a mold release agent,asa release agent in textile printing inks to permit ready removal ofink compositions from printing screens, as a textile sewing lubricant,as a lubricant for drilling bits including those used in oil welldrilling, and as a lubricant and polish for wood, leather, plastic, andother surfaces.

It is, therefore, an object of the present invention to provide afluorocarbon telomer in the form of a finely divided dispersion inwater. Another object is to provide a useful aqueous composition of afluorine-containing wax-like material in colloidal form. Still anotherobject is to provide a process for readily dispersing the material inwater to provide a stable, finely divided dispersion.

These and other objects will become apparent in the fol lowingdescription and claims.

The heretofore described objects are accomplished by mixing, with atetrafluoroethylene telomer dispersed in l,1,Z-trichlorotrifluoroethane,a water-soluble surface active agent, distilling off about one-half the1,1,2-trichlorotrifluoroethane solvent, and slowly adding Water withstirring as the solvent continues to be removed whereby the telomer isdispersed as a stable, finely divided, waterdilutable suspension in thewater solution of the surface active agent.

More specifically, the present invention is directed to an aqueousdispersion of a fluorocarbon telomer stabilized with a water-solublesurface active agent, said telomer being produced by reacting, at 75 C.to 200 0, one mole of tetrafluoroethylene in the presence of from about2. to about 3 moles of 1,1,2-trichlorotrifiuoroethane, from 0.01 mole to0.1 mole of an active telogen, and. from 205% to 3% by weight of anorganic peroxide catalyst based upon said tetrafiuoroethylene.

This invention is also directed to a process of preparing an aqueousdispersion of the tetrafluoroethylene telomer heretofore described,which process comprises add ing, to the dispersion of the telomer in1,1,2-trichlorotrifluoroethane, a water-soluble surface active agent,distilling oif about one-half of the 1,1,2-trichlorotrifiuoroethane, andslowly adding water with agitation as the solvent continues to beremoved whereby the telomer becomes dispersed as a stable, finelydivided suspension in the water solution of said surface active agent.

The telomer taken for dispersion in a water solution of a surface activeagent is that prepared by polymerizing amount of active telogenincreases. M if much more than 3 moles of trichlorotrifluoroethane is 1mole of tetrafluoroethylene in the presence of about 2 to about 3 molesof trichlorotrifl-uoroethane and 0.01 to 0.10 mole of an active telogen,this polymerization being carried out in a closedsystem with a peroxidecatalyst at a temperature within the range of C. and 200 C. and atautogenous pressure.

This telomer dispersed in 1,1,2-trichlorotrifiuoroethane is obtained byuse of telomerizat-ion techniques, as de! scribed, for example, in US.Patent No. 2,540,088. In,

Pressures will be generated between about 300 and 600 p.s.i.g. and asthe reaction nears completion, the pressure Within the system will beobserved to drop.

- In preparing this tetrafluoroethylene telomer dispersedin1,1,2-trichlorotrifluoroethane, it is necessary to'carefully control theamounts of tetrafluoroethylene, trichlorotrifiuoroethane and activetelogen. For each mole of tetrafiuoroethylene, it is necessary to havepresent, in the reaction mass, 2 to 3 moles of trichlorotrifiuoroethane,and, from about 0.01 to about 0.10 mole of active telogen. If less than0.01 mole-of active telogen is used, the product is of higher molecularWeight and is less Wax-like, approaching, ethylene itself. If much above0.10 mole active telogen is used per mole of tetrafluoroethylene, themolecular weight becomes too low and the properties of the productprogress from wax-like to grease-like to liquid as the used per mole oftetrafluoroethylene, the dispersion is too dilute for practicalpurposes. If less than about 2.5

moles of the trichlorotrifluoroethane is used, the viscosity of theresultant product is very high, resulting in poor heat transfer duringpreparation. It is important to carry out the process Within the ratiosdescribed to obtain the present novel dispersion.

It has been established by chemical analysis that thetrichlorotriliuoroethane takes part in the telomerization process; saidtrichlorotrifluoroethane acts as a telogen to some extent. Thus, itfollows that the Wax-like product obtained is probably a mixtureoftelomers; one species being a reaction product of tetrafiuoroethylenewith the trichlorotrifluoroethane and another species being the reactionproduct of tetrafluoroethane with the actve telogen. The final product,then, is a dispersion of these wax-like compounds in thetrichlorotrifluoroethane.

The trichlorotrifiuoroethane maybe either isomer; i.e.,

it may be 1,1,l-trichlorotrifluoroethane or1,1,2-trichlorotrifiuoroethane; it is preferred to use the latterisomer.

The term active .telogen" utilized according to the present inventiondescribes a telogen which is well known in the art and is one ofnumerous compounds. Representative active telogens are'tertiaryhydrocarbons such as isobutane, methylcyclopropane, 2,2-dimethylbutane,methylcyclohexane, etc.; atomsisuch as tetrahy etc; amines such astn'methylamine, triethylamine, etc.; alcohols such as methanol, ethanol,isopropanoL'sec- Patented Oct. 1, 1963 as the telogen is decreased,polytetrafluoro-- On the other hand,

ethers with alphahydrogen rofurane, diethylether, diox-ane,

butyl alcohol, cyclohexanol, etc.; bivalent sulfur compounds such asethyl mercaptan, dirnethyldisulfide, etc.

The active telogen, although present in very small amounts, contributessignificantly to the obtaining of the fluorocarbon telomer withoutundesirable by-products. If the telomerization is carried out withoutthe active telogen, high molecular weight products are obtained whichare not wax-like. The presence of the active telogen in the amountsspecified results in products having a molecular weight in the order of2000; TFE polymers of this molecular weight have wax-like properties.

As indicated, the reaction is carried out with a peroxide catalyst. Thiscatalyst may be any organic peroxide which generates free radicals atthe reaction temperature. Based on availability of catalysts andconvenienoe temperatures of about 75 C. to about 200 C. will usually beused and the catalyst employed will be chosen according to its abilityto generate free radicals at the specific temperature selected. Thecatalyst usually employed will be benzoyl peroxide, di-tert-butylperoxide, or ethyl peroxide. With di-tert-butyl peroxide, whichis thepreferred catalyst, a temperature of 130 C. will be used. Theconcentration of catalyst taken vwill usually be in the range of .05 to3% by weight of TFE, the preferred amount being about 2%.

The preferred telomer is that prepared by reacting tetrafiuoroethylenein the presence of 1,1,2-trichlorotrifluoroethane, methylcyclohexane,and di-tert-butyl peroxide. By Way of illustrating how the telomer maybe prepared the following procedure is given.

A clean, dry lO-gallon stainless steel, steam-jacketed autoclave,equipped with a cooling coil, anchor-type agitator, and intake anddischarge tubes, is flushed with nitrogen and filled with a solution of1,1,2-trichlorotrifiuoroethane containing 0.76% by weight ofmethylcyclohexane and 0.28% by weight of di-tert-butyl peroxide. Thetake-o1f valve is set for 600 p.s.i;g. and the temperature raised to 160C. The above 1,1,2-trichlorotrifluoroethane solution is then fed to theautoclave at a rate of 68.7 lbs. per hour. At the same timetetrafluoroethylene under a pressure of 650 to 750 p.s.i.g. isintroduced into the autoclave at a rate of 20 lbs. per hour. When asteady reaction state is reached -a dispersion of a tetrafluoroethylenetelomer dispersed in 1,1,2-trich1orotrifluoroethane at a solidsconcentration of about 20% is obtained.

The surface active agentused to stabilize the aqueous dispersion of thetetrafluoroethylene telomer may be of the anionic, cationic, non-ionic,or amphoteric type. It is added to the dispersion of the telomer in the1,1,2-trichlorotrifiuoroethane solvent in which it is prepared. Fromabout 0.05 part to 2 parts, preferably from 0.3 part to one part, ofsurface active agent per part of telomer may be employed. The amount ofsurface active agent taken will depend on the concentration of thetelomer in the most dilute aqueous dispersion to be made; in general,the more dilute the dispersion the more surface active agent is requiredto keep the telomer particles from coagulating. V

In accordance with the present invention, amounts of surface activeagent less than 0.05 per part of telomer may be insufficient to providea stable, non-coagulating dispersion, particularly at an ultimate highdilution with water to give a dispersion having a solids content of theorder of 0.5%. Amounts of surface active agent in excess of 2 parts perpart of telomer may be used but such amounts are generally not needed asthey consume an excessive quantity of material without increasing thestability of the resultant dispersions, and may interfere with theusefulness of the telomer contained in or deposited from the dispersion.

,The anionic surface active agents that may be em-' played in thepreparation of the aqueous dispersion of this invention include sodiumoleate, sodium stearate, di-

butylarnrnonium' oleate, morpholine salt of oleic acid,

sodium salt of wood rosin acids, potassium salt of dehydrogenated woodrosin, alkyl (C -C sodium sulfate, alkyl (C -C sodium sulfate, sodiumsalt of sulfated alkenyl (C -C acetate, sodium 0-sulfato(methyl Istearate), sodium salt of naphthalenesulfonic acids/formaldehydecondensation product, sodium salt of lignosu1- decylammonium chloride,hexadecyltrimethylammonium b r o m i d e, (dodecylmethylbenzyl)trimethylammoniurn.

chloride, benzyldodecyldimethylammonium chloride;N-(Z-diethylaminoethyl)oleamide hydrochloride; olcic acid diester ofN,N,N',N-.tetrakis(2-hydroxypropyl)ethylene diamine singly quaternizedwith dimethyl Sulfate. Non-ionic surface-active agents that may beemployed include condensation products of'ethylene oxide with hexylphenol, isooctyl phenol, hexadecanol, oleicv acid, alkanethiol (C -Calkyl (C -C amines, sorbitan monolaurate. Alkyl(C C )methylglucaminephate and Z-(dimethylamino) stearic acid, methyl ester, betaine areexamples of amphoteric surface-active agents (agents that are cationicwith acid and anionic when alkaline) that may be employed to stabilizethe aqueous dispersion of the telomer.

' Preferably from one-half to three-fourths of the 1,1,2

trichlorotrifluoroethane contained in the dispersion of thetetrafluoroethylene telomer which is to. be dispersed in water isremoved by distillation before the water is added to make the aqueousdispersion. This avoids excessive foaming that may occur with distillingthe solvent from the starting telomer dispersion when water is presenttogether with the surface-active agent. The remainder of the solvent isremoved by distillation as the water is slowly added after at leastone-half of the solvent has been distilled off. Although 25% or less ofthe 1,1,2-

trichlorotrifluoroethane originally present in the solvent dispersion ofthe telomer may be retained in'the sub-' sequently prepared aqueousdispersion, it is preferable to remove at least of the solvent, andusually all of the solvent will be removed.

After the addition of the surface active agent water' is added to thesolvent dispersion of the telomer, but

preferably to a 1,1,Z-trichlorotrifluoroethane dispersion containing atleast 50% of the telomer.' The water is added slowly at first withmoderate agitation to provide. mixing of the aqueous and organic phasesof the composition while the remainder of the solvent is distilled off.As the solvent removal nears completion the balance. of thewater isadded to give the desired concentration of The total amount of waterwill vary from 0.5 part to 2000 parts per part of tetraiiuorm ethylenetelomer, .preferably from about 2% parts to '4 parts of water per partof telomer will be used to tproe vide aqueous dispersions of from about30% .to 20% aqueous dispersion.

solids content. More concentrated dispersions, however,

may be optionally made: by adding less Water. The 20% j to 30%concentrated dispersionmay, of course,;be diluted with water toprovidestable, dilute dispersions or dilute dispersions may be prepareddirectly'by in-' creasing the amount of water added to the aqueoussystem during the initial dispersion of the telomer in the water.

Representative examples illustrating the present in vention follow.

.The surface active agents, proportions of telomer. and 7 water andsurface active agent, and conditions'employed in preparing the aqueousdispersions of the telomer in phos-- Examples 1 to 4 are summarized inTable I which follows:

wire and excessive wear of the die orifice take place, and the drawnwire is non-uniform in gauge.

TABLE I.-SUMMARY OF EXAMPLES Solvent Telomer Surface Active AgentSolvent Water Added Dispersion Removed Telomer When Water Content Ex.Parts/ Added Amt. Parts of Product Amt. Part of in g. Per PartDispersion Amt. Percent Telomer Amt. Telomer of Teloin Perin g. Telomerin g. in g. Amt. Per met cent ing. cent of Total 1 l, 250 16 200Morpholine salt of oleic acid 1 166 0.83 510 50 640 a 3.2 20 2 1,500 20300 {233%l datif?fffii fi fi fi fiiitk: 38 81%} 150 62 490 31 3 3, 2809. 2 302 Oleic acid diester of N, N, N, Ntetra- I 180 0.6 1, 500 52 7502. 24. 3

kis-(Z-hydroxy-propyl) ethylenediamilifietsingly quaternized withdimethyl su a e. p 4 2, 500 500 Condensation product of ethylene oxide250 0.5 1, 300 65 250 0. 5 60 and isooctyl phenol.

1 The concentration of the active ingredient was 30%.

Example 1 ANIONIC DISPERSING AGENT A 3 1. round bottom glass flaskfitted with a half-moon stirrer, dropping funnel, and a downwardcondenser was charged with 1250 g. of a dispersion oftetrafluoroethylene telomer prepared as described above and dispersed in1,1,2-trichlorotrifluoroethane to have a 16% solids content. To thistelomer dispersion was added 166 g. of the morpholine salt of oleicacid. Under mild agitation and with heat from an oil bath about one-half(510 g.) of the trichlorotrifluoroethane was removed. Then 640 g. ofwater was slowly added through the dropping funnel while continuing thedistillation of the organic solvent. When the vapor temperature reached62 C. the heating was discontinued. The resulting product was a viscousmilky-white liquid having dispersed therein the tetratluoroethylenetelomer to give a solids content of 20%. As a component of a textileprinting ink the telomer dispersion provides a ready release of the inkfrom the printing screens.

Example 2 MIXED ANIONIC DISPERSING AGENTS The reaction flask of Example1 was charged with 1500 g. of a 20% dispersion of thetetrafluoroethylene telomer in 1,1,2-trichlorotrifluoroethane and 150 g.of an aqueous solution of a sodium alkyl (C benzenesulfonate containing30% active ingredient. The flask was heated in an oil bath, and 750 g.of 1,1,2-t1ichlorotrifluoroethane distilled ofif. Then 125 g. of waterwas slowly added to give a viscous grease-like material. Upon theaddition of 60 g. of sodium stearate the viscous mass thinned to afluid. At this point an additional 365 g. of water were added as theheating was continued until a total of 1200 g. ofl,1,2atrichlorotrifluoroethane was removed. The resulting product was afinely divided dispersion of the telomer having a solids content of 31%and containing none of the trichlorotrifluoroethane as free solvent.When diluted with water to provide 0.5% telomer dispersion, the dilutesuspension remained stable for several days with only slight settling.The mildest agitation, such as obtained by merely inverting thecontainer, served to redisperse any separated solid material.

By employing the product telomer dispersion as a lubricant, aberyllium-copper alloy wire can be directly drawn smoothly, uniformly,and with little or no interruption by breakage. In the absence of thesubject lubricant and employing a conventional wire-drawing lubricant,the alloy wire is first coated with copper to improve the Wire drawingoperation and the quality of the resultant wire and the coating issubsequently removed before the Wire is used. Without the copper coatingwith a conventional lubricant, excessive breakage and scarring of theWhen the product telomer dispersion is used as a cutting fluid in metalworking on a lathe less tool wear is encountered than when aconventional cutting oil is employed.

Example 3 CATIONIC DISPERSING AGENT To the reaction flask of Example 1was charged 3280 g. of a 9.2% dispersion of the tetrafluoroethylenetelomer in 1,1,2-trichlorotrifluoroethane and 180 g. of the oleic aciddiester of N,N,N',N'-tetrakis(Z-hydroxypropyl) ethylenediamine singlyquaternized with dimethyl sulfate.

With heating the flask in an oil bath 1500 g. of the tri- Example 4NON-IONIC DISPERSING AGENT To the reaction flask used in the previousexamples was added 2500 g. of a 20% dispersion of thetetrafluoroethylene telomer in 1,1,2-trichlorotrifluoroethane and 250 g.of a condensation product of ethylene oxide and isoootyl phenol. Theflask and its contents were then heated on an oil bath until 1300 g. ofthe triohlorotnifluoroethane were removed. At this stage the slow,dropwise addition 'of 250 g. of water was begun while continuing theheating until a vapor temperature of 60 C. was reached. During thisfinal distillation the remainder of the solvent and g. of water wereremoved. The resulting product was a white paste that comprised 60%telomer dispersed in water with particles that were electrically neutraland thereby rendered compatible with either anionic or cationic surfaceactive agents which might be added to the aqueous telomer dispersion orwith which the telomer dispersion might come into contact.

Example 5 WATER-IN-OIL TYPE DISPERSION OF TELOMER To the reaction flaskpreviously employed was added 1250 g. of a 16% dispersion of thetetrafluoroethylene telomer in 1,1,Z-trichlorotrifluoroethane, 40 g. of9-octadecen-l-ol (technical grade from sperm oil), and 20 g. of sodiumsteal-ate. 530 g. of 1,1,2-tricl'11orotrifluoroethane were distilledfrom the mixture. Then the dropwise addition of 500' g. of water wasbegun with agitation while the removal of the chlorofluoroethane solventwas continued until the vapor temperature reached 55 C. A total of 900g. of the solvent was removed together with 150 g. of the added Water.The resulting product was a thick white paste containing 26% of thefluorocarbon telomer. A dispersion of 200 g. of the telomer in. 150 g.of residual solvent formed a continuous phase with 350 g. of waterdispersed therein. Such a Waterin-o'rl type dispersion is a goodlubricant and/or polish for leather, wood, plastic, and metal surfaces.

Any of the described water-soluble surface active agents, activetelogens, and organic peroxide catalysts may be substituted in thepreceding representative exampics to give substantially the sameresults.

As many apparently Widely different embodiments of this invention may bemade without departing from the spirit and scope thereof, it is to beunderstood that this invention is not limited to the specificembodiments thereof except as defined in the appended claims.

The embodiments of the invention in which an exclusive propenty orprivilege is claimed are defined as follows:

1. An aqueous dispersion of a wax-like fluorocarbon telomer stabilizedwith a Water-soluble sunface active agent, said telomer being producedby reacting, at a temperature Within the range of 75 C. to 200 C., 1mole of tetrafluoroethylene in the presence of from about 2 to about 3moles of 1,1,Z-trichlorotrifiuoroethane, from 0.01 mole to 0.1 mole ofan active telogen, and from 0.05% to 3%, by weight, of an organicperoxide catalyst based on said tetrafluoroerthylene.

2. A composition according to claim 1 wherein the water-soluble surfaceactive agent is the morpholine salt of oleic acid, the active telogen ismethylcyolohexane" and the organic peroxide catalyst is di-ttert-butylperoxide.

3'. The process of preparingian aqueous dispersion of a Wax-likefluorocarbon telomer stabilized with a watersoluble surface activeagent, which process comprises adding a water-soluble surface activeagent to the telomer produced by reacting at to 200 C. 1 mole oftetrafluoroethylene in the presence of fromabout 2 to about 3 moles of1,LZ-trichlorotrifiuoroethane, from 0.01 mole to 0.1 mole of an activetelogen, and from 0.05% to 3%, by weight, of an organic peroxidecatalyst based on said tetrafluoroethylene, followed by distilling offabout one-half of said 1,1,2-trichlorotrifluoroethane and slowly addingwater thereto under conditions of agitation as said1,1,2'trichlorotrifluoroethane is distilled off.

References Cited in the of this patent UNITED STATES PATENTS 7 2,540,088Barrick Feb. 6, 1951 2,575,041 Bauer Nov. 13, 1951 2,885,448 Miller uMay 5, 1959 2,993,857 Sudhuiz July 25, 1961 2,975,132

Ferm Mar. 14, 1961

1. AN AQUEOUS DISPERSION OF A WAX-LIKE FLUOROCARBON TELOMER STABILIZEDWITH A WATER-SOLUBLE SURFACE ACTIVE AGENT, SAID TELOMER BEING PRODUCEDBY REACTING, AT A TEMPERATURE WITHIN THE RANGE OF 75*C. TO 200*C., 1MOLE OF TETRAFLUOROETHYLENE IN THE PRESENCE OF FROM ABOUT TO ABOUT 3MOLES OF 1,1,2-TRICHLOROTRIFLUOROETHANE, FROM 0.01 MOLE TO 0.1 MOLE OFAN ACTIVE TELOGEN, AND FROM 0.05% TO 3%, BY WEIGHT, OF AN ORGANICPEROXIDE CATALYST BASED ON SAID TETRA FLUOROETHYLENE.